


Caracal

by 796116311389



Category: Sherlock (TV)
Genre: Cat/Human Hybrids, Coping, Doctor John Watson, Friends to Lovers, M/M, Other Additional Tags to Be Added, Slow Burn
Language: English
Status: In-Progress
Published: 2020-02-02
Updated: 2020-02-27
Packaged: 2021-02-28 04:00:59
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 2
Words: 4,407
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22517410
Author URL: https://archiveofourown.org/users/796116311389/pseuds/796116311389
Summary: Sherlock clutched his arm where the cat had scratched him. It had left five neat marks on his arm. He grimaced, but determined they would be fine.No stitches at least.He didn't tell John.Less than a week later he wished he had.
Relationships: Sherlock Holmes/John Watson
Comments: 18
Kudos: 59





	1. Chapter 1

**Author's Note:**

> Many thanks to Iwantthatbelstaffanditsoccupant and Sprinkledoodler for being betas.

Sherlock clutched his arm where the cat had scratched him. It had left five neat marks on his arm. He grimaced, but determined they would be fine. 

No stitches at least.

He didn't tell John. 

Less than a week later he wished he had. 

**********************

John is at work and Sherlock is feeling sick. He writhes around naked on his sheets, his body hot and sore. His spine feels like it's on fire and his head is throbbing. 

Sweat soaks him and he is so thirsty. He carefully pushes himself up and out of the bed and takes a couple of steps into the bathroom. His body is pale save for two red spots high on his cheekbones. His hair is a mess and stuck up in odd angles. He runs his hands through his hair and gasps at how sensitive his scalp has become. 

Suddenly he feels dizzy and collapses slowly to the bathroom floor, first to his knees and then completely, feeling the coolness of the tiles. He clutches his head as a burning intense pain rips through him, starting in his skull and then continuing down his spine. He convulses and arches. It feels like the pain will never end, but suddenly it's quiet except for his heavy panting. 

It suddenly occurs to him that he had been screaming. He's glad Mrs Hudson is away, for he surely would have given her a heart attack with the noise. He's not so glad John isn't there because he needs a doctor. 

More than a doctor...he needs John. 

He feels something soft brush against his leg and startles. He's weak from whatever that pain was, but he still manages to scramble to a seated position up against the wall. He looks down between his legs and realises there is a long, black tail leading from his backside. He stares at it and it twitches. He feels the twitch. He realises it's a part of him.

He picks it up gingerly and shudders at the sensation. The fur is soft, silky, and dark brown like the hair on his head, but shorter and slightly stiffer. 

His head. 

He drops the tail and brings his hands shakily up to his hair and scalp. 

Oh God.

He has _cat ears_. 

In addition to his regular ears he now has cat ears with long, furry tassels on their tips. 

He crawls over to the sink and pulls himself to standing. His mouth gapes open as he stares at his reflection in the mirror. Cat ears, covered in the same fur as his tail, protrude from his head, and when he concentrates he can swivel them and flatten them like a housecat.

He's breathing heavily, panic just below the surface. 

What the hell has happened to him? 

His eyes drift to the faded cat scratch on his arm. He must have been infected with...with something. This is too bizarre and he's too exhausted to consider what's happened to him further. He manages to stumble back into his room and into his bed. He doesn't want to lie on his back because it forces him to acknowledge his tail, so he lies spread-eagled across his sheets on his front. His tail lies quiescent, a black line rising from above his pert bum, down the line of his crack and straight down the sheets to his ankles. 

He's still hot and achy, but most of the searing pain that had consumed him before has dissipated. He lays like that for hours, or possibly merely minutes, he doesn't know. 

He sleeps. 

He wakes to the sound of the hall door opening and John setting his bag on the table. 

He feels an irrational panic and need to hide, an instinct so strong he almost scrambles under his bed. He only just stops himself. 

"Sherlock?"

He can hear John making his way down the hall and freezes in panic. There's no hiding his _condition_ from John, but a feeling close to embarrassment makes him want to.

He closes his eyes as John knocks on his door and calls his name again, then after a moment slowly opens the door. 

And then slams it shut.

Sherlock's head pokes up at that.

"Jesus. Sherlock! If you were wanking you could have just fucking said." 

Sherlock tilts his head at John's statement, "I'm not wanking. I was _sleeping._ "

"And what? You just forgot to take your sex kink stuff off?"

"My what?"

"The fucking tail Sherlock."

Sherlock looks over his shoulder and down his back where his tail responds by perking up off his bum slightly. A shiver runs down his frame. He can feel where the bed brushes against his tail, a foreign sensation, but not entirely unpleasant. 

"Oh. That. Actually, could you come in here, John?"

There's a long suspicious silence before John responds, "What for?"

"You won't believe me unless you're in the room."

Another moment passes and then John is slowly stepping into Sherlock's room as if Sherlock were a predator who at any moment could devour him. 

John gives Sherlock's body a good look starting at his toes all the way to his...his..., "Oh God. You have the cat ears too."

Sherlock looks on as John's face turns a scarlet color. Fascinating.

"John. Please don't be alarmed-"

"That is the number one phrase that alarms me."

Sherlock gives John a glare before continuing, "As I was saying, please don't be alarmed, but I have grown a cat tail and ears this afternoon."

Much to Sherlock's surprise John gives a sputtering laugh, "I'm sorry. Are you high?"

Sherlock draws his head back and scrunches up his face, affronted, but most surprisingly- and this stops John's laughter at once- he lets out what can be best termed a growl. From somewhere deep in his chest, a short warning noise. His tail also perks up slightly and puffs in warning. 

"Sherlock. What was that?"

Sherlock for his part is equally startled and looks at John helplessly, "I'm not sure. I told you. I had a fever this morning and then I _grew_ cat ears and a tail and now apparently I can growl quite convincingly."

Sherlock watches as John settles into a more serious mood, his face reflecting his concern.

"You're serious."

"Completely. Feel free to come closer and see for yourself."

John does just that. He starts up at Sherlock's ears.

He hesitantly reaches out and touches the tip of the cat ear closest to him. 

The sensation is immediate and electric and Sherlock twitches his ear away from John's touch and jerks his head back slightly. 

John pulls his hand back quickly and gives Sherlock a questioning look. 

"Sensitive."

John nods his head in understanding, "Ok." He looks around the room, avoiding looking at Sherlock. "Are you hungry?"

As if on cue, Sherlock's stomach gives a rumble. "So it would seem."

John looks down at a spot next to Sherlock's head, "Why don't you put something on and I'll order in?"

Before Sherlock can respond John leaves the room, clearly overwhelmed.

Sherlock dawdles a moment and listens to the sounds of John rustling through their menu drawer for something to order; then realizes that he can _literally_ hear the quiet shuffling of the papers over one another as if John were in the same room.

He listens in amazement for a moment before getting up onto shaky legs and going to his dresser drawers. 

He pulls out an older pair of pajama trousers, grabs a pair of scissors from his bedside drawer and cuts a hole in the bottom for his tail. He doesn't bother with pants. Why ruin more than one piece of clothing? 

He slips the trousers up and works his tail into them. He forgoes a shirt for now because he's still pretty warm. He also, for some vague reason he can't explain, just knows putting a shirt on would be very uncomfortable. If he's being honest with himself, the trousers are already almost borderline too much. 

He walks out through the kitchen and into the lounge and perches on the back of his chair so his tail can move freely. John watches him from his own chair. He's made both himself and Sherlock tea. 

They stare at each other for a long moment before John clears his throat, "So, let's go over the medical facts first. How are you feeling? What other symptoms are you experiencing...besides the obvious?"

Sherlock cocks his head and considers John's question, "I would say in general I feel healthy. Certainly better than this morning before this happened. Symptoms. Aside from the obvious, I'm also warmer than is typical, my auditory abilities seem to have improved dramatically." He pauses and takes a heavy sniff of the air. "I'd also say my olfactory sense is more sensitive than before this happened. Ah, and I don't know how relevant these two facts are but, when you came home I experienced a heightened sense of panic that was atypical for me and currently I have a conflicting feeling of not wanting to have anything touching my skin and..." 

John waits but Sherlock doesn't continue. "And...what?" John asked curiously. 

To John's surprise Sherlock looks away and covers his face with his hand, "...and to have my skin stroked."

John purses his lips but doesn't comment. "Ok. Do you have any idea at all what may have caused this?"

Sherlock keeps his face turned from John, but his ears and tail betray him. His ears twitch down, flattening slightly, and his tail begins lashing anxiously. 

John gives a sigh, "Sherlock. Don't bother lying about it. You clearly know what possibly caused this."

Sherlock faces John again this time clearly annoyed by his new emotive body parts, "Last week, when I went to do research for that banker case, I was scratched by a cat. Here." He turns up his arm and shows John the neat row of pink scratches, nearly healed. "I thought it was superficial and typically cats don't transmit rabies, so why should I be concerned?"

John levels his gaze at him, "I can think of a few reasons to be concerned. Cats carry more than just rabies, Sherlock."

Sherlock's tail puffs up, clearly gearing for a verbal spat, but before he can say a word, the doorbell rings and two things happen at once:

Sherlock startles so badly he _actually hisses_ and falls off the back of his chair.

And John fails to catch him. 

John leans over the back of Sherlock's chair to look down at the detective on the floor. Sherlock has his arms crossed and is scowling up at John, face pink with embarrassment at his overreaction. 

The bell goes off again. 

"You okay?"

"I'm fine. Just go get our damn food."

And that's how John knows Sherlock is very much not fine, but he goes to fetch the food from the courier anyway. 

When he returns, Sherlock is in his chair rubbing his body all over it. John stands in the doorway a moment, then, "Another symptom, is it?"

Sherlock freezes looking guilty as anything, his newest appendages reflecting a sense of contriteness as they curl and press into him.

John just tries his hardest not to smile at Sherlock's ridiculousness. 

Sherlock carefully removes himself from John's chair and walks haughtily into the kitchen. John rolls his eyes and follows, setting their food on the table. 

The meal is easy and when they finish John makes them both more tea since they never really got to drink it earlier. They stay at the kitchen table and simply exist with each other for a while. After half of John's tea is gone he clears his throat.

"So. I may have an idea of what happened to you. Granted it's been nearly 20 years, but I believe I may have heard a case of something similar in class. I'll have to look it up, but, yeah."

"Well? What do you think happened to me? I've never heard of anything like this before."

"It was in our historical health class. You know, where you learn about ancient surgeries or whatever? Well, apparently this," John gives a wave of his hand to the whole of Sherlock's person, "is something that used to happen. It was still rare back then, but because of the closer living between animals and humans it did happen on occasion."

"Ok. Did your class speak of how they became better?" 

" Uh, no. And I'm fairly certain this is it. This is permanent."

Sherlock feels his stomach drop, "Permanent? You mean I'll be like this? This? For forever? No, no, nooooo." He drops his face into his hands and just lets out a despairing groan.

John winces at the hysteria he hears in Sherlock's voice. His heart goes out to the man. After all, in some ways it's no different than any other life-altering illness. 

He gets up, rounds the table, and places a hand on Sherlock's shoulder. He notes how warm Sherlock's pale skin feels. He knows Sherlock is a man, the same as he is, but he sometimes forgets that Sherlock isn't as cold as the attitude he puts forth. Sometimes he forgets that Sherlock, in so many ways, is more feeling than anyone he's ever met.

John pulls out a chair and sits next to Sherlock, and in a soft voice speaks, "Hey. It's okay. I mean, yeah this happened and we can't change it, but. We'll get through it. You just need to adjust and I will help you every step of the way."

Sherlock relaxes and leans into John's hand slightly while John speaks, and when John finishes what he has to say looks into John's face, into his eyes, "You will?" 

John's face does multiple things at once but settles into a softly fond expression and he smiles, "Of course. You're my best friend."

Sherlock blinks multiple times and turns bright pink. He looks away from John and, to his own mortification, begins purring quietly which only makes him turn a brighter shade of red. He puts his face into his hands and gives another groan at his body's betrayal of his inner emotions. 

John can't help but smile at the audible confirmation that his words have affected Sherlock in some way. He slowly starts stroking his hand across Sherlock's back, fingers occasionally grazing the curls at his nape. Sherlock's blush recedes, but his purr remains constant. 

"Don't worry, Sherlock. We'll make it through this."

"Promise?"

"I promise."


	2. Chapter 2

Sherlock woke in the early hours the next day. He was on his front, his lower back aching. He had refused to sleep on his back, to avoid acknowledging his new form, but now, he was paying the price. He rolls to his side and curls up into a ball. He can feel where his tail moves between the sheets. 

It curls around him and despite the fact that he abhors it touching him, reminding him of how he's changed, it's also comforting in a way. It eases him in the same way as crossing one's arms. 

Carefully, he reaches down and pulls the tip of his tail up so he can take a better look at it. It's soft and heavy, but flexible. He moves it around and tests how flexible it is. He bends it over itself until the first twinges of pain. 

He notes its limits and then gives it a steady, gentle tug. Again, he pulls until he begins to feel pain. He adds an additional mental note to never ever let anyone else pull his tail. The idea of the pain it would cause makes his stomach drop and his whole body shiver. He drops the tail and lets it resume its subconscious role of hugging him. 

He brings his hands up and gently probes at his new cat ears. 

Their skin is fine and delicate. Like his normal ears, squeezing them doesn't elicit much of a feeling, but pulling them or using his nails to pinch is quickly painful. However, gently rubbing the short hairs on the ears against their grain is a subtly pleasurable sensation. He loses himself in the feeling for a moment, before using his fingers to explore the inside. 

They are filled with soft fur but most definitely a second set of hearing organs. They lead into his head the same as his regular human ears do. 

He rolls onto his back, brings his hands down, and steeples them under his chin. His tail curls up between his legs and wraps around him once more. 

He frowns and realizes his discomfort with his situation has him _literally_ tucking tail. And now, with that thought, he can feel his ears flatten to his head. 

He hates this. His every thought and emotion elicits responses that he has no control over. 

His body is not his own.

As someone who prides himself on his ability to conceal, to hide everything behind a mask of cold indifference, this is the true horror. He can get used to a tail and extra ears, can even rationalize their value, but they leave him so vulnerable. 

They are a weakness. 

His whole career depends on his ability to convince others of what he sees. To lie to suspects and victims alike to find the solution to the mystery du jour; his _whole identity_ depends on his ability to do this.

How can he convince others of his invulnerable confidence when his tail betrays his nerves with every twitch?

How can he charm someone if his ears flatten in displeasure at the sight of them?

And _John_? 

How can John keep putting up with him if he can no longer do the work? That's the trade off after all: he provides excitement and John puts up with his moods. John will try to fix him, but when he can't help he'll become frustrated and leave. Sherlock suddenly realizes that his tail has puffed up and he's snarling at the thought. He rolls to his front again and sighs. 

Stupid new body parts. 

Stupid new instincts.

Stupid. 

He's so _stupid_. 

He thinks back to yesterday evening and how John had been so understanding, despite this being an absolute shock.

Is John that calm because he has an ulterior motive? He's a doctor and Sherlock has just become a medical mystery. Is that where his concern comes from, or was he being sincere when he said he was Sherlock's best friend?

Sherlock contemplates John lying to him, or worse: simply being unfaithful, and the fierce feeling of _Never, he's mine!_ catches him off-guard. 

Where did _that_ come from? 

Admittedly, he's always been a bit touchy about the possibility of John leaving (and there's that aggressive feeling of possession again), but not like this. 

He thinks back to the day before, when a similar feeling compelled him to rub up into John's chair. John had left and Sherlock needed to make sure he smelt of John and that when John returned he would smell of Sherlock. An overwhelming urge to ensure that everyone knew John was part of _his_ family.

His contemplation is interrupted by John's call from the kitchen.

"Sherlock? You up? I've made breakfast."

Sherlock takes a sniff of the air and smells bacon, sausage, eggs, beans, and hash. The smell makes him realize he's ravenous. 

"Be out in a minute!" 

He gets out of bed and slips on his pajama bottoms, still too warm and too sensitive to put on any other clothes.

He walks into the kitchen and John looks at him before focusing back on the eggs in the pan. "Still feeling hot?"

Sherlock takes a seat, "Yes, though definitely better than the day before."

"That's good." John finishes the eggs and puts them on two already fully loaded plates, sets the plates in front of each of them, and takes a seat. "I know you ate a lot at dinner last night, but you're probably still hungry from yesterday and your metabolism has increased in general."

"How do you know that?" Sherlock starts tucking into his meal but regards John with an inquisitive gaze. 

"Well. After you went to bed I did a bunch of internet searches and I also called up Mike to see if they had anything in the hospital library. He dropped off a book this morning, and between that and the internet, I've got a general idea of what's happened to you and what you can expect." 

Sherlock pauses his eating, his ears flattening to his head, "You didn't tell Mike what's happened to me, did you?"

"No. I didn't think you'd want that. I figure you'll decide when and how you want to share with others."

"Good. Thank you." Sherlock relaxes and gives a gentle pleased purr. He cringes internally at the sound, but is helpless to stop it. He hasn't entirely determined the reflexive muscles that control his purr and what it is that prompts it. He picks at his food for a minute. "So what else can I expect?" 

John shakes his head. "Finish eating, we'll talk after breakfast. There's a bit to go through and I don't want you getting distracted."

Sherlock scrunches his face. "Is that another cat symptom?"

John laughs, "No, that's just a _you_ symptom. I know you and you'll get so distracted by the information and, I'm sure, questions you'll have, that you'll forget all about your food. However, you've just been through a major biological change in many ways akin to puberty, and you need all the calories you can get. Eat. We'll talk after."

Sherlock purses his lips in disappointment, but on reflection he knows that John is right. He doubles down and shoves the food into his mouth, chewing and swallowing as quickly as he can, pointedly ignoring John's amused smile. 

After breakfast they move to the living room, take their respective seats, and John takes a deep breath before beginning.

"Ok. So first things first, a small caveat. Almost all the information available is either anecdotal from actual cat people or their spouses or from extremely niche scientific papers. So. We should be prepared for anything, but here's the gist of what is known.

"There's an estimated four hundred cat people worldwide. It's estimated because the majority of infections and changes happen in countries where reporting and healthcare in general aren't that great. As of right now, you are the only known cat person in Europe. The last case of this condition on the European continent was a woman at the turn of the last century. It's her husband's journal that provides most of the anecdotal knowledge."

"And the scientific papers?"

"Are almost entirely focused on the chemical changes which occur, and not on the actual physical and behavioral changes you can expect. It's interesting and definitely worth a read, but not valuable to the day-to-day. Which is why I already emailed you the links and you can peruse them on your own. However, I went ahead and read the book and made a small list of things to expect. You can read the book too, but given its flowery language and your general demeanor, I thought you'd prefer me to summarize."

"I'll read it for myself, but I do appreciate your summarizing it for me. So. You leave me in suspense. What's in store for me? Please don't tell me I'm going to grow fur all over."

John gives a short back of laughter. "No, thank God. Could you imagine the shedding?" He gives another low chuckle before getting serious again, "No, no fur, but there are some behavioural things. Some of which I think you're already experiencing."

At the mention of behavioural changes Sherlock gives a grimace, his ears flatten, and his tail lashes agitatedly, but he doesn't interrupt. 

"From the account I read, you'll likely experience a quicker fight or flight response, a more possessive take on things you perceive as yours, supposedly a craving for more meat in your diet, and an increased need for attention. Though of course all of this is for one person told from the perspective of another. We can't be sure how much of this was unique to her and how much of this is common to cat people in general."

Sherlock nods, "Some of it seems general. I am experiencing some of that."

"Which things?"

"The fight or flight response, and the possessiveness. It's mostly flight with the first."

"That's interesting."

"How so?"

"The husband described his wife as quicker to fight after the change. So that bit sounds like it's partly down to character...I'm surprised it's not fight for you too."

Sherlock's ears, which had been flat during most of John's explanations, betray his inner thoughts as they flick forward, alert, and then press back down. "You know me. I don't actually seek out other people unless I have to," he explains delicately. "But back to the summary. Anything else?"

"Yeah, physically you're stronger, faster, and more resilient now. Night vision will be better. You'll probably want to sleep more though, too. Tradeoffs and all that."

Sherlock gives a dismissive wave. "Once I've had some practice and experience with my new… me," he gestures vaguely to his whole self, "I should be able to return to more or less how I normally was."

John raises his eyebrows, "We'll see. So. What now?"

"Now we wait the day out until we can go out tonight."

"Go out? Where? And why?"

"To practice, of course. I can't learn to use my new appendages or develop new skills if I'm cooped up in the flat. I'll just throw my coat and that damnable Deerstalker on and we'll go to a secluded place I know. I'll be able to work on myself and you'll be there to help me." Sherlock could feel himself beaming, his ears perking towards John and his tail wrapping around his own shoulders caressing himself. He couldn't figure out why his plan was making him so darn happy, though. It was just exercising under John's watchful eye. 

"Alright then. After dinner we'll go. I'll bring a pack snack too, since I'm sure all that activity will make you hungry." John smiles back at Sherlock and Sherlock starts purring again. He's really got to figure out what's triggering it, but he'll do it later. Right now, it's soothing and it makes John's smile wider.


End file.
